TopStyle supports HTML, XHTML, and CSS editing in various revisions, along with powerful checking for standards and browser compatibility issues. Checking optionally covers a variety of levels, such as a strict W3C CSS specifications, to issues on a wide variety of browsers. This style checker feature not only provides detailed warning messages but enables the user to visually see if parts of HTML or CSS code would be incompatible with a particular browser.

TopStyle 3.5 was released on October 15, 2007 (version 3.5.0.9). New features include better support for Windows Vista and browsers released since TopStyle 3.12 (Safari 2, IE7, Firefox 2, Opera 9), Box Spy (tool that shows padding/margins of boxes in the preview window), and many more including a large number of bug fixes and improvements.

TopStyle 4 was released on May 31, 2009. New features include (UTF-8) unicode support, live FTP editing, support for browsers released since TopStyle 3.5 (IE8, Firefox 3, Safari 3, and Safari 4), Script Insight for ASP + PHP + ColdFusion, support for iPhone (and iPod touch) webapp development, support for HTML 5, IE8 document compatibility, and many more including a large number of bug fixes and improvements.

TopStyle 5 was released in November 30, 2012, including support for CSS3.